JASON NGUYEN – MINH PHAM
TRUONG NGUYEN – HUNG PHAM

AGENDA
1. BLOCKCHAIN
2. ETHEREUM
3. SMART CONTRACT & ERC20

1. BLOCKCHAIN
• WHY USE A BLOCKCHAIN ?
• WHAT IS A BLOCKCHAIN ?
• HOW A BLOCKCHAIN WORKS ?

WHY USE A BLOCKCHAIN ?
Problems ?

WHY USE A BLOCKCHAIN ?
• Centralized system
• Integrity problem
• Security problem
• Stability problem
• Decentralized distributed
system
• Immutability
• Consensus

WHAT IS A BLOCKCHAIN ?
• Blockchain is a shared database, consisting of a ledger of
transactions
• Full decentralization
• Extreme fault tolerance
• Independent verification

HOW A BLOCKCHAIN WORKS ?
• Transaction: interaction between accounts in a blockchain
network
• Block: a bundle of transactions
• Blockchain: chain of blocks

HOW A BLOCKCHAIN WORKS ?
2 31
6 5 4
Someone requests a
transaction
The requested transaction is
broadcast to a P2P network
consisting nodes, combined
with other transactions in last
block
Miners compete to validate
the block with new set of
transactions using
cryptography hashing.
The transaction is complete The new block is then added
to the existing blockchain.
Once verified, this block is
represented as a new block.

HOW A BLOCKCHAIN WORKS ?
• Miner - Mining
• Nodes which have opted to be miners
compete to solve math problems which
secure the contents of a block
• Once a new block is mined, the other miners
are notified and begin verifying and adding
this new block to their copies of the chain
• The winner of the competition receives some
cryptocurrency as a reward

HOW A BLOCKCHAIN WORKS ?
• Proof of Work (PoW) and Proof of Stake
(PoS)
• PoW: miners do mining to create new block
by
• verify transactions
• find signature
• rewarded by new digital currencies

HOW A BLOCKCHAIN WORKS ?
• Proof of Work (PoW) and Proof of Stake
(PoS)
• PoS:
• The creator of a new block is chosen in a
deterministic way, depending on its wealth,
also defined as stake
• No block reward
• The miners take the transaction fees
• All the digital currencies are previously
created in the beginning, and their number
never changes

2. ETHEREUM
• Ethereum is:
• An open blockchain platform
• Anyone can build and use
decentralized applications that
run on blockchain technology

ETHEREUM
• Founders: Vitalik Buterin
(inventor), Gavin Wood and
Jeffrey Wilcke
• Proposed in 11/2013
• Implemented in 2014
• Circulating supply >98M ETH,
• Market cap ~60B

ETHEREUM VS BITCOIN
• Similarities:
• Uses blockchain as a distributed database
• No one controls or owns Ethereum
• Ethereum network is a peer-to-peer system
• Has its own monetary unit: Ether

ETHEREUM VS BITCOIN
Differences:
• Block time:
• Bitcoin: ~10'
• Ethereum: ~12"
• Monetary supply:
• Maximum 21M coins
• Unlimited - 0.3 times the total amount of the pre-sale per year
• Sidechain
• Ethereum: Provide to developers a system to build software's for general purpose on-chain
computation
• Smart contracts - ERC20

ETHEREUM VS BITCOIN
Uncle blocks

ETHEREUM
A sidechain is a separate blockchain that is attached to its parent
blockchain using a two-way peg

ETHEREUM
• The original design of blockchain
• Ethereum designed to evolve the
blockchain from a distributed
transactional database to be part
of a general purpose peer-to-peer
computing framework
• Ethereum Virtual Machine

ETHEREUM
• On Ethereum, blockchain was modified with each block not only
contains transactions but also the state of member programs

SMART CONTRACT – ERC20
JASON NGUYEN

3. SMART CONTRACT & ERC20
• What is a smart contracts?
• What is ERC20?
• What is a sidechains?

WHAT IS A SMART CONTRACTS?
• Proposed by Nick Szabo, who coined the term, in 1994
• Is a computer protocol intended to digitally facilitate, verify, or
enforce the negotiation or performance of a contract
• Can accept and store ether, data, or a combination of both
• Programmable
• Written in a language called Solidity. Solidity syntax is similar to
JavaScript

WHAT IS A SMART
CONTRACTS?
• If this Then this
• Decentralized trust
• Code on Blockchain
• Store rules and terms of contract
• Execute agreed terms
• Readable

HOW SMART CONTRACTS WORKS?

HOW SMART CONTRACTS WORKS?

HOW SMART CONTRACTS WORKS?

HOW SMART CONTRACTS WORKS?

HOW SMART CONTRACTS WORKS?

WHAT IS ERC20?
• A common list of rules that an Ethereum token has to
implement, giving developers the ability to program how new
tokens will function within the Ethereum ecosystem, in 2015
• Became popular with crowdfunding companies working on
initial coin offering (ICO) cases
• Is not a technology, software, or piece of code. It is a technical
specification. If a token implements the spec, it is an ERC20
token

WHAT IS A SIDECHAINS?

WHAT IS A SIDECHAINS?
• Is a separate blockchain that is
attached to parent blockchain
• Are decentralized, peer-to-peer
networks that provide useful
enhancements (such as security,
risk, and performance) for global
systems
• Enable developers to safely
develop new applications without
a risk

CURRENT SIDECHAINS PLATFORMS
•RSK (short for Rootstock)
• It has attached with the Bitcoin blockchain
• Enable the Bitcoin blockchain to have smart contract capabilities
• Make payments much faster
• Ardor’s Blockchain
• The first scalable blockchain-as-a-service platform
• Uses the PoS (Proof of Stake) consensus mechanism
• Most transactions are pushed down to the childchain (sidechain) level
• Global entities such as assets and currencies across chains can be
accessed through childchains

I KNOW YOU’RE TIRED, BUT
FINISH WITH ENERGY AND
ENTHUSIASM